Ivan probably understood Miles better than any other person his age, except possibly for Emperor Gregor. He provided muscle and speed that Miles lacked, and was frequently the go-between for other characters who dealt with Miles. He often complained that he was Miles's "donkey," but nevertheless followed where Miles led; this was equal parts knowing that Miles was right, and acceptance of his family responsibility. In return, Miles trusted Ivan more than he trusted almost anyone else: when Ivan first called himself Miles's donkey, Miles answered, "I don't know what I'll be asking you to carry, but it could be high explosives ... I need a donkey I can trust."

Ivan's association with Miles Vorkosigan proved hazardous to his well-being and his life on more than one occasion. In childhood, this mostly included getting caught in a cave-in from a tunnel Miles made him dig. In later years, he was captured by renegade Cetagandan haut while on Eta Ceta, and then during a posting to Earth, he was captured and held hostage by Komarran terrorist Ser Galen and Miles's clone Mark specifically in order to draw Miles into a trap.

In the months leading up the the Imperial Wedding of Gregor Vorbarra and Laisa Toscane, Ivan was drawn into the conflict between Lady Donna Vorrutyer (who had had Betan gender-change surgery to become Lord Dono, in order to inherit her brother's estate) and her less-than-savory cousin Richars (who would otherwise inherit). Rudely surprised by Donna's transformation, Ivan found himself enmeshed in the plans to have Dono affirmed by the Council of Counts. This culminated in his assisting in the thwarting of a direct attempt to reverse the Betan surgery with far more crude field surgery. In the event, Ivan managed to finally get one up on Miles by turning his usual "Ivan, you idiot!" back on itself and proving himself to have significantly aided Dono's case as well as Miles' related one.

In this and other books, Ivan showed himself to be physically competent and possessed of a keen sense of judgment about people. However, despite his apparent showiness, he was perennially modest about such useful talents, which often led people to underestimate him.

As he aged into his thirties, Ivan discovered two new senses: a sense of responsibility and a sense of loss. His mantras throughout life had been "It's not my fault" and "I want nothing to do with it." Despite the trials his cousin Miles inflicted on him over the years, he found himself shocked and dismayed when Miles, in trouble over his relationship with Ekaterin Vorsoisson, repeatedly refused his help. Later Ivan's reaction to an attack on Dono was revulsion at the nature of the attack, even though he had previously been blindsided by Dono's sex change. As he said, "I don't agree with what you did, but what they tried was just ... wrong." Having helped abort the attack he used his political connections to bring Dono's cousin to justice. His reward for this was a nod and a rare smile from Emperor Gregor, and the sudden realization that, in Miles' words, the reward for a job well done is usually a harder job.

Ivan also realized that he was losing the attraction he once held for young vivacious Vorbarr Sultana debutants. While recovering from having been strung along by one, just to get her boyfriend to pay more attention to her, he was hit hard by Lady Donna's sex change, especially since he had been thinking about renewing their old relationship. Having already been turned down by two of the Koudelka girls, and facing a shortage of eligible partners due to Vor parents' selecting for male children in his generation, he realized that the life of a carefree bachelor could well become that of a lonely bachelor.

The tale of how he found a wife is told in Captain Vorpatril's Alliance.

For most of his early life Ivan was known colloquially as "That Idiot Ivan" or "Ivan, You Idiot". He was tall, handsome, popular with women, and the despair of his mother.

Despite the impression he gave of foolishness and over-sexedness, he grew up into an extremely capable worker; by the time of the end of Captain Vorpatril's Alliance, he was able to transform the Barrayaran embassy on Ylla into an effectively-run enjoyable place to work, using only "average effort for a slow day at Imperial Headquarters"[2].